Electromagnetic switch



March 4 1924.

N. A. WOLFE ET AL ELECTROMAGNETIC SWITCH Filed May 14 1921llllllllllllllllllllllllll llllln."\'

Inventors Nbble fLWolfe,

Eu ene Fons,

Their flttorne g residing, res

Patented Mar. 4, I

UNITED STATES NOBLE A. WOLFE, OI NIBKAYUNAAND EUGENE FONS, OFSCEENECTADY, NEW YORK,

PATENT oFncs.

ABBIGNOBB TO GENERAL ELEJTBIC COMPANY, A CORPORATION 01' NEW YORK.

ELMBOMAGNETIC SWITCH.

Application filed ma 14, 1921. Serial r... 469,503.

To all whom it may concern:

Be it known that we, N onus A. Wonrn and EUGENE Poss, citizens of theUnited States, tively, at Niska una, in the count of So enectady, State0 New York, and tady, State of New York, have invented certain new anduseful Improvements in Elec tromagnetic Switches, of which the followingis a specification.

Our invention relates to improvements in electric switches for openingand closing electric circuits, and the invention has for its object theprovision of an improved electromagnetic switch which shall be simple inconstruction, cheap to manufacture and one which shall nevertheless bereliable in operation.

The invention relates to features of construction and arran ement whichwill be particularly disclose hereinafter and the scope of the inventionwill be indicated by the claims.

In carrying the invention into efi'ect in one form, we provide anoperating electromagnet with a movable magnetic member,

preferably a plunger, supported within the electromagnet. A pivotedstrap is adapted to embrace the electromagnet so as to cooperate withboth ends of the plunger to be operated thereby and a switch memberisadapted to be reciprocated by the strap between two definite positionsresponsively to the reciprocations of the plunger. A resilientconnection is provided between the switch member and the strap, and thearrangement is such that the switch member is thrown with a snap actionfrom each of its definite positions to the other position, andresiliently held in the last position to which it is thrown by theoperation of the plunger. To provide for reciprocating the plungerwithin the electromagnet, the electromagnet may be provided with twocoils, so that when one coil is energized the plunger is moved in onedirection, and when the other coil is energized the plunger is moved inthe opposite direction.

For a better understanding of the invention reference is had to theaccompanying drawings in which we have shown an embodiment of ourinvention for purposes of illustration, and in which Fig. 1 is a planview of an electromagnetic switch constructed in accordance with theinvention; Fig. 2 is a side view of the same; Fig. 3

chenectady, in the county of Schenecis a detail perspective view of theswitch operatin mechanism; and Fig. 4 is a very simpli ed diagram of amotor control arrangement embodying the electromagnetic switch shown inFigs. 1 to 3.

magnetic switch comprises an electromagnet having a two part winding,the one part designated by the numeral 10 and the other part by thenumeral 11. The electromagnet 1s provided with a movable magneticmemher, the plunger 12 which is suitabl supported within the winding ofthe e ectromagnet. This plunger is adapted to reciprocate the pivotedswitch member 13 back and forth on its pivotal support between twooperative positions.

The strap 14 is adapted to embrace the operating electroma net so as tocoo rate with both ends of the plun er 12 to reciprocated back and fortha out its pivotal support 15 responsive to the reciprocations of theplunger of the electromagnet. A resilient connection is rovided betweenthe for the purpose of tilting the switch member about its pivotalsupport with a snap action and for holding the switchmember resilientlyin'the osition to which it has been thrown by t e last operation of theplunger 12. This resilient connection comprises the spring 16 secured tothe strap 14 by means of the 0 amp 17 and the sprin loop 16 carries aroller 18 which is adapted to cooperate with the cam surface of aninsulating block 19 pivotally mounted on the post 20. The resilientlymounted movable Referring to the drawings, the electro-.

pivoted strap 14 and t e switch member 13 contact 21 is suitably securedto the right;

hand end of the block 19, and the resiliently mounted movable contact 22is secured to the left hand end of the block 19. Each of these contactsis adapted to make engagement with either one of a set of oppositelydisposed stationary contacts which form the circuit terminals of thedevice.

The operation of our invention, asthus constructed and arranged and withthe arts in the various positions shown in the rawings, will beunderstood from a consideration of Fig. 4 taken in connection with theother figures. The electromagnetic switch of our invention is adapted tocontrol the armature circuit'of an electric motor 23 at the will of theoperator or in response to some predetermined condition. Inthe-arrangement shown in Fig. 4, the electric motor is adapted to becontrolled responsively to the operation of a thermostatic circuitcontroller 24, and it will be understood that the circuit controller 24may be either is connected to the source of supply 25 by means of ourimproved electromagnetic switch, the circuit being from the lower supplyconductor through the movable contact 22, the motor armature, throughthe movable contact 21 to the upper supply conductor. If thethermostatic circuit controller 24 is operated to make engagement withthe stationary contact 26, the part 10 of the winding of theelectromagnetic switch will be energized from the supply circuit througha circuit including the movable contact 22, the part 10 of the winding.thermostat 24, contact 26, movablecontact 21 to the other supplyconductor. The plunger will thereupon be attracted within the winding 10and be moved quickly to its left hand position. In moving to the,leithand position, the plunger will carry with 1t.the strap 14 and movethis strap clockwise about its pivotal su port. The resiliently mountedroller 18 will also be moved about the pivotal support 15 for the strap,and by reason of thefact that the roller 18 cooperates with the camsurface of the member 19, the roller 18 will be moved forward on the camsurface until it has been moved past the ridge of the cam surface.Moving upwardly along the cam surface, the Spring 16 is put understrain, so that when the ridge of the cam surface has been passed theswitch member 13 will be quickly tilted to its other position by theenergy stored in the spring 16. The switch is thereby operated from oneposition to its other position with a sna action, and the switch isresiliently held in the position to which it is thrown by the lastoperation of the plunger 12.

When the switch is thus moved to its other position, the electric motoris deenergized and the circuit through the part 10 of the winding of theelectromagnet is also deenergized. It will be observed that the circuitfor the winding of the switch is opened at the main contacts instead ofat the thermostatic contacts, so that pitting and burning of thethermostatic contacts are thereby prevented.

When the thermostat 24 makes engagement with the stationary contact 27,the part 11 of the winding of the operating electromagnet is energizedthrough a circuit including the movable contact 22, the contact 27,thermostat 24, winding 11, movable contact 21, to the other supplyconductor. The plunger 12 will thereupon be moved to the position shownin Fig. 4, andthe switch member 13 will be tilted quickly to theposition shown in the drawings with a snap action and will beresiliently held in that position by means of the spring 16, in a mannerwhich will be well understood by those skilled in the art from thedescription of the operation which has been previously given.

It will be observed that our invention has features of simplicity ofconstruction and arrangement, and that the switch will be reliable inoperation by reason of the fact that there are comparatively few partsto get out of order. It will also be observed that by reason of the factthat the magnetic movable member of the operating electromagnet is aplunger supported so as to be freely reciprocated within the operatingwinding of the electromagnet, the operation of the switch will be quickand positive in any event. It will also be observed that currents ofconsiderable capacity may be interrupted without the riskof seriousarcin at the contacts. It will also be observe that very powerfulmagnets may be employed to insure the quick make and quick bleak actionof the switch member. Althou 'h the opening and closing of the maincircuit of the switch is positive in any event, the particular partofthe winding which was energized to effect the movement of the switchmember from one position to the other is deenergized as soon'as it hasperformed its intended function. The switch winding is therefore onlyenergized during the time that the switch is in operation, and thecurrent taken by the switch is comparatively small.

In accordance with the provisions of the patent statutes, we havedescribed the principle of operation of our invention, together with theapparatus which we now consider to represent the best embodimentthereof, but we desire to have it understood that the apparatus shown isonly illustrative and that the invention can be carried out by othermeans. 7

What we claim as new and desire to secure by Letters Patent of theUnited States, is:-

1. An electromagnetic switch comprising an operating electromagnethaving a reciprocable plunger, a movable strap embracing the saidelectromagnet cooperating with both ends of said plunger to be op eratedthereby. a switch member operated back and forth between two positionsby the said strap. and resilient means for biasing the switch member tothe position to which it is moved by the last operation of the plunger.

2. An electromagnetic switch comprising an operating electromagnethaving a reciprocable plunger, a pivoted strap embracing ineweo theelectromagnet cooperating with both ends of the said plunger to beoperated thereby, a pivotally mounted switch member, and resilient meansconnecting the said strap and switch member for reciprocating the switchmember about its pivotal support responsively to the reci rocation ofthe the said plunger to be operated thereby, a pivotally mounted switchmember havin a cam surface and a resiliently mountefi roller connectingthe said strap and switch member for cooperating with the said cam nsurface to reciprocate the switch member about its pivoted support witha, snap ec'tion responsively to the reciprocation of the plunger and forresiliently holding the switch member in the position to which it 25 ismoved by the last operation of the plunger. In witness whereof, we havehereunto set our hands this 12th day of May, 1921.

NOBLE A. WOLFE. EUGENE PQNS.

